Improvement in ellipsographs



Vto the shaft in any desired manner.

Letters Patent N. 91,681, daad .ame 22, 1869.

IMPROVEMENT IN ELLIPSOGRAPHS.

The Schedule referred to in these Letters Patent land making part cf the same.

To all whom it Imay concern Be it known that I, ANDREW SMITH, of Dayton,v

in the county of Yam Hill, and State of Oregon, have invented a new and improved Ellipsograph 5 and l do l hereby declare that the following is a full, clear,land

exact description of the construction and operation of the same, reference being had to the acconmanying drawings, making a part of this specification in which- Figure 1 is a side view;

Figure 2, a bottom view; and

Figure 3 a section through line :c x ot' g. '1.

The object ot' this invention is to provide Vfor public use a simple, cheap, and effective instrument for drawing ellipses, and so constructed that it can be easily adjusted to produce iigures of any practicable size and shape.

In thedrawings- A is a bii'urcatcd standard, arranged with its forked end downward, and terminating in sharp brads a' a', which hold the instrument .firmly upon the drawingcard or paper. At its upper end thestandard A tel'- .minates in a hinge, a, which connects it to a horizontal arm, B, one end of which it supports, as shown in fig. 1. i i i C is an upright metallic staff, terminating at its lower end in a needle, c, which sticks into the drawing-card or paper, as shown in iig. and, with the two needles` a' a', holds the instrument inI position.

A short distance above theneedle, and capable of being adjusted up or down on the stati', so as to enlarge or diminish. the figures without changing. their shape, is a pattern, D, ot' elliptical shape, andattached At its upper end, the staff cxt/endsthrough themend of the arm B, as

` seen in lig. l, and may be clamped in any position by means of a set-screw, b.

This staff, thusconstructed and attached to the arm l B, serves to support a vertically-sliding and horizon- Vtally-revolving block, E, which is pressed downward by f a spn'ng, s, at its upper end. rlhis block is provided with lugs e, to which is jointed an arm, F.

The arm F, at its lower end, is attached to and supports a nearly horizontal piece, G, that serves, among other uses, as a handle ly which to rotate the arm F, and its supporting-block E, about the vertical stad' or spindleG.

The inner end of the part Gr presses against the periphery of the patternl), against which it is held by the action of a spring, t. lt may, it' thought necessary, be provided with a friction-roller, r, which shall travel around the edg'e of the pattern in the manner that will bc readily understood from the drawing. A curved guide and brace, H, attached to the block E, and extending through a slot in the arm F, may he employed to prevent the joint at e from injury by tor- Sion.

In a groove in the under side of the piece G is fit-f ted a metallicslide, Lwhich can be adjusted in or out,

with reference to the spindle G, by means of a thunnbscrew, J. Y

l'lhe pencil K is supported by the inner end ot" the slide I, and moves in or out with it. Any practicable method of attaehingthe pencil, to the slide may be employed, but that which l employ is as follows:

A screw-stem, L, is fastened to the slide I, projecti ing downward from it. A hollow sleeve, or tub'e, M, screws upon this stein, and a tube, N, which holds the pencil, slips over or into the tube M. The whole arrangement is clearly shown by figs.` 1 and 3. i

The under side of the part G may be. graduated, as shown in fig. 2, so that the effect which any movement of the slide I will have upon the figure to be drawn, may he accurately calculated beforehand.

The whole instrument is exceedingly simple, `and perfectly adjustable in all its parts.

I am aware that an instrument somewhat resembling a combination of staff C, pattern D, arm F, and pencil K, has been heretofore employed for this purpose, and I do not claim such an arrangement, irrespective of the other parts herein described and-shown.

The advantages of my improved instrument over the one referred to are, among others, the following,

viz:

First, the two legs a'a, in connection with the needle c, support the instrument more rmly and steadily.

Secondly, the joint a enables it to be folded very compactly when not in use.

Thirdly, by placing the spring s above the block,

instead of inserting it above the pencil, in the tube N,

as in the instrument referred to, the action of the.

spring is not so much interfered with by the friction or cramping of the pencil in the tube, as the arm Fis rotated around the spindle.

Fourthly, the guide H supports the arm F more peifectly.

Fifthly, the pencil is more easily and perfectly adjustahle, by means of the slide I and screw J.

Sixthiy,'the part G serves as a more convenient handlel for moving the pencil.

Seventhly, the friction-roller causes the parts to work more easily.

H aving thus described my invention,

NVhat I claim as new, and desire to secure by Betters Patent is In connection wit-h the standards A Aand arm B, I claim the combina-tion and arrangement of t-lle stad' C, block E, arm F, pattern D, guide H, springs t's, slide l,.screw J, and pencil-holder, all constructed to operate lsubstantially as and for the purposes specified.

` ANDREW SMITH.

Witnesses:

JAMES H. GRIDLEY, Unas. A. Per'rrr. 

